#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

int main(){

	double r,v;
	double pi = 3.14;
	 cin >> r;
	 v = 4.0/3 * pi * pow(r,3);
	 cout << fixed << setprecision(2) << v;

    return 0;
}
